const nodeList = document.querySelectorAll("box");
console.log("querySelectorAll type:", Object.prototype.toString.call(nodeList)); // querySelectorAll type:: [object NodeList]

const htmlCollection = document.getElementsByTagName("div");
console.log("getElementsByTagName type:", Object.prototype.toString.call(htmlCollection)); // getElementsByTagName type: [object HTMLCollection]

const DOMTokenList = document.querySelector("div").classList;
console.log("classList:", DOMTokenList);

// 字符串
const str = "abc";
console.log(Object.keys(str));
console.log(Array.from(str));
